Marik Ishtar is the main antagonist of the Battle City story arc in Yu Gi Oh!. He is a former tombkeeper and the leader of the Ghouls (also known as Rare Hunters). He owns the Millennium Rod, allowing him to take control of anyone, sometimes to the extent of speaking through them. In the overall story of the Battle City arc, Marik serves as the main antagonist, but later his alter ego took over and replaced him as the main antagonist.
When Marik Ishtar was born, it was decided by his father that he should be the next tombkeeper. However, unlike his adopted older brother Rishid, he did not want to be a tombkeeper, and out of his hatred for the Pharaoh, his evil side, Yami Marik, was born. When Marik and his sister Ishizu snuck out (which was strictly forbidden to do!), and his father found out, he was about to banish Odion, when Yami Marik took over Marik's body, took the Millennium Rod and stabbed Marik's father to death (while in the 4Kids version, he sent his father to the Shadow Realm).
In the Japanese manga version of Yu-Gi-Oh! the ghost of Shadi told him that his fate and his father's death was the Pharaoh's fault. Because of this, Marik set out to kill the pharaoh and gain his memory for himself to break free from his family's duty, which he regards as enslavement.
Marik set out to take over the world, using his army of Rare Hunters to find the three Egyptian God Cards. He soon came to possess two of them, the Celestial Dragon of Osiris and the Winged Dragon of Ra. His goal is to exact his revenge on the Pharaoh (he only wants to take over the world in the 4Kids adaptation).
He found "Bandit" Keith Howard (who was fighting for his life in the current after being ejected off the island by Maximillion Pegasus) and turned him into his mind slave with his Millennium Rod. Speaking through Bandit Keith, Marik stole Yugi Muto's Millennium Puzzle and dueled him over it (as it had to be won from him), but the duel was interrupted with Yami Bakura severed his control over Keith.
Marik's Rare Hunters illegally entered Kaiba's tournament in Battle City so they could defeat Yugi and Kaiba (who possessed the third God Card, the Giant God Soldier of Obelisk) to take the Millennium Puzzle and Obelisk. After one of the Ghouls, Rare Hunter 1, lost a duel to Yugi, Marik took over his body and trapped his soul in the Shadow Realm. His next Ghoul was Pandora the Conjurer, who dueled Yugi, and whom he had convinced to join up with him by lying and saying that he would bring his ex-girlfriend (whom he drove away) back to him. Arkana lost to Yugi. Afterwards, Marik dueled Yugi through his mind slave the Pantomimer, who possessed the Celestial Dragon of Osiris, but against all odds Yugi defeated him and took Osiris. Marik then went to Battle City himself and teamed up with Yami Bakura, while posing as a good man named Namu in order to fool Yugi and the others.
Next, Marik sent two Ghouls, the Masks of Light and Darkness, to defeat Yugi and Kaiba and their God Cards, but the Mask of Darkness was defeated and presumably sent to Hell (or the Shadow Realm in the English version). Marik then possessed the Mask of Light and trapped his soul in the Shadow Realm, telling him that Anzu Mazaki and Katsuya Jonouchi had been kidnapped.
Marik used his Millennium Rod to possess Jonouchi in order to make him challenge Yugi to a duel in which the loser would be drowned, but Joey fought Marik's control and drove him out with Yugi's help, and in the end, both of them survived. Marik entered the Battle City finals, telling Rishid to pretend that he is Marik. After Rishid was knocked out by the Winged Dragon of Ra for playing a counterfeit Ra card, Yami Marik could no longer be contained.
Seconds after revealing his true identity to Yugi, Marik was taken over by Yami Marik. From here, he remained trapped inside Yami Marik's mind, though he was able to speak through Anzu, and appear alongside Yami Bakura as he dueled Yami Marik and lost, trapped in the Shadow Realm.
Enter the Shadow Realm
Marik appeared beside Yami Marik as he dueled Yami Yugi, just as Yugi appeared alongside Yami, in a shadow duel that the loser's other half would vanish into Hell or simply be destroyed. It seemed that the situation was hopeless, as even if Yami Marik was defeated, it would be the original Marik (who is now good) who would vanish, but when Yami destroyed the Winged Dragon of Ra in their duel, Marik and Yami Marik were switched around, so that Yami Marik was the victim and Marik regained control of his body. Realizing and accepting his destiny to help the Pharaoh fulfill his, Marik surrendered the duel to Yami, and Yami Marik was destroyed. He then gave Yami his Millennium Rod and Winged Dragon of Ra, making Yami possessor of all three Egyptian God Cards and one more of the seven Millennium Items.
Dawn of the Duel
After Zorc Necrophades and Yami Bakura were destroyed, Marik appeared alongside Rishid and Ishizu to witness the final duel between Yugi and Yami, in which Yami would have to lose in order to go through the door and rest with his guardians. Their duties as tombkeepers were finally completed when Yugi won and Yami walked through the door.
- In the Battle City arc, while Marik himself is the main antagonist, Yami Marik acts as the Bigger Bad and still has an influence in the events. So, in a way, Marik acts as the Dragon to himself. However, when Yami Marik finally becomes his own person, Marik eventually turns against him.